Knowledge, attitude, and practice toward photoaging in the Chinese population: a cross-sectional study

To investigate the knowledge, attitude, and practice (KAP) of photoaging in the Chinese population. This web-based cross-sectional study was conducted between January 2023 and March 2023 among the Chinese population aged 18–80 years old. Participants’ knowledge, attitude, and practice toward photoaging were collected through a self-administered questionnaire. A total of 830 questionnaires were collected, with 826 valid questionnaires and an efficiency rate of 99.52%. There were 274 (33.17%) males and 532 (64.41%) aged 31–51 years old. The average knowledge, attitude, and practice scores were 7 (4, 9) (possible range 0–12), 31.5 (28, 34) (possible range 8–40), and 33 (24, 42) (possible range 11–55), respectively, indicating poor knowledge, good attitude, and moderate practice. Spearman correlation analysis showed that knowledge was negatively correlated with attitude (r = − 0.111, P < 0.05) and practice (r = − 0.113, P < 0.05), and attitude was positively correlated with practice (r = 0.992, P < 0.05). The multivariable linear regression model showed that for each point increase in attitude score, the practice score increased by 2.96 points (β = 2.96, 95% CI 2.91–3.01, P < 0.001). The Chinese population has poor knowledge, good attitude, and moderate practice toward photoaging. A good attitude toward photoaging would lead to good practice, and more outreach and education for the Chinese population might be needed.

Understanding the Chinese population's KAP toward photoaging may be the cornerstone of designing successful interventions to identify knowledge deficits and promote anti-photoaging behaviors in the Chinese population.Therefore, this study aimed to investigate the KAP of photoaging in the Chinese population.

Knowledge, attitude, and practice dimensions
In knowledge dimension, the highest scoring question was K1 (Skin aging encompasses both intrinsic and extrinsic factors.Intrinsic aging refers to the natural aging of the skin due to the decline in cellular metabolism associated with the aging process, resulting in the skin aging naturally.Extrinsic aging, on the other hand, is attributed to environmental factors from the external surroundings that contribute to skin aging.), with a correct rate of 86.80%.The lowest scoring question was K6 (The SPF indicated on sunscreen reflects its protective ability against UVB.Generally, a higher SPF number suggests an extended duration of protection against sunburn.
[False]), with a correct rate of 8.11% (Table 2).In attitude dimension, A8 (Sunlight can replenish vitamin D. It can also replenish calcium, prevent and improve osteoporosis, so there is no need for sun protection.[Negative]) had the most people choosing very negative, followed by A7 (High-powered sunscreens can be a burden to my skin, so I am reluctant to use them.
[Negative]) and A2 (I get very anxious when I think of my skin aging due to photoaging. [Negative]) (Fig. 2).In practice dimension, P3 (Topical application of appropriate concentration of tretinoin [Positive]) had the most people choosing very negative, followed by P2 (Routine use of antioxidants [Positive]) and P1.4 (Reapply every 2 to 3 h [Positive]) (Fig. 3).The specific levels of KAP differed between participants of different genders (P < 0.05) except for A2 (Anxiety due to skin aging caused by photoaging) and A8 (Sunlight can replenish vitamin D. It can also replenish calcium and prevent and improve osteoporosis, so sun protection is not necessary); by household monthly per capita income level at K1-K3 (the basics of photoaging) (P = 0.022), A4 (Sun protection is not only to be anti-aging but also to fight cancer) (P = 0.026), A5 (Sun protection is needed not only in summer, but all year round) (P < 0.001), A6 (Although I can accept natural aging, I still think it is important to prevent photoaging) (P < 0.001), and P1.1-P1.5 (Reduce skin exposure and use sunscreen products) (P < 0.001), P2 (Routine use of antioxidants) (P = 0.011) and P4 (Chemical peel agent treatment) (P < 0.001), P5 (Laser and intense pulsed light) (P < 0.001), P6 (Radiofrequency microneedling) (P < 0.001) and P7 (Mesotherapy) (P < 0.001); by education levels at A6 (Although I can accept natural aging, I still think it is important to prevent photoaging) (P = 0.030); by residence type at A8 "Sunlight can replenish vitamin D. It can also replenish calcium and prevent and improve osteoporosis, so sun protection is not necessary) (P = 0.002), P1.1-P1.5 (Reduce skin exposure and use sunscreen products) Table 2. Distribution of knowledge dimension.a False refers to the statement that the question stem is wrong.b According to Chinese regulations, SPF labeling shall not be higher than 50, while some countries allow SPF values higher than 50.

Knowledge N (%)
Correct answer Wrong answer/unclear K1: Skin aging encompasses both intrinsic and extrinsic factors.Intrinsic aging refers to the natural aging of the skin due to the decline in cellular metabolism associated with the aging process, resulting in the skin aging naturally.Extrinsic aging, on the other hand, is attributed to environmental factors from the external surroundings that contribute to skin aging.( True (P = 0.004), P2 (Routine use of antioxidants) (P = 0.008), P4 (Chemical peel agent treatment) (P = 0.010), P5 (Laser and intense pulsed light) (P < 0.001), P6 (Radiofrequency microneedling) (P = 0.002) and P7 (Mesotherapy) (P = 0.022), and there were significant differences at age except for K4-K10 (UV and Sun Protection) (Supplementary Table S1).

The univariate and multivariate linear regression analysis
The univariate and multivariate linear regression analysis showed that for each point increase in attitude score, the practice score increased by 2.96 points (β = 2.96, 95% CI 2.91-3.01,P < 0.001) (Table 4).

Discussion
This study found that public in China had poor knowledge, good attitude, and moderate practice toward photoaging, and good attitude leads to good practice, proving the need for more popularization of photoaging knowledge among the public in China, which may provide a reference for future targeted educational efforts.
The results are consistent with other studies in which knowledge and awareness of the harmful effects of sun exposure are widespread in China, and increased awareness of the risks does not necessarily lead to good behavior 11,14 .According to the announcement of the State Food and Drug Administration (SFDA) 15 , the Sun Protection Factor (SPF) value should not be higher than 50.It may not be known by many people and therefore got a very low correct rate in K6 (8.11%), which may make consumers think that foreign products have better sun protection when choosing product.The K4 also got a low correct rate (9.56%).According to the different wavelengths, the ultraviolet rays in sunlight are mainly divided into UVA, UVB, and UVC; UVB will increase a lot in summer, and although the wavelength is shorter than UVA and will not invade the dermis or even the subcutaneous tissue area, it is highly mutagenic and can cause skin redness, molting, itching, dryness, and keratin damage [16][17][18] .These information should be disseminated among the general public.
One study suggested that there is little consensus about sun exposure among physicians 19 , which may lead to confusion about the relationship between sun exposure behaviors, sun protection behaviors, and vitamin D, as reflected consistently in A8.Daily and/or recreational use of daily broad-spectrum sunscreens with high UVA protection does not impair vitamin D status in healthy individuals 20 , which requires more education.
Tanning is only one manifestation of UV damage to the skin, but photoaging is actually much more than what is visible to the naked eye; it is more frightening than natural aging 21 .Retinoic acid promotes collagen synthesis in www.nature.com/scientificreports/photoaging skin and has been widely used in cosmetics and dermatological treatments 22,23 .UV radiation causes severe oxidative stress that stimulates skin aging, leading to melanogenesis and wrinkle formation, and antioxidants are considered an important strategy for treating skin photoaging [24][25][26] .In this study, however, the application of retinoids and antioxidants in the Chinese population was not positive, which may need to be improved.The results of this study was somewhat different from other studies 27,28 , in which men, those in non-urban areas, and those with household monthly per capita income ≤ 5000 had higher attitude and practice scores.With the rapid development of economic level, there is a growing awareness of the harmful effects of sunlight on the skin and the importance of sun protection, which may be facilitated by the media and cosmetic companies' publicity and advertising.
A dissociation was observed in the present study regarding the correlations between knowledge, attitude and practice.Indeed, it is generally acknowledged that better knowledge will translate into better attitude and practice 29,30 .Still, such a dissociation has been reported in medical students toward geriatric education, in whom improved knowledge did not translate into a better attitude 31 .Still, in the present study, this population had poor knowledge, but good attitude and moderate practice.It could be due to the television, radio, and internet advertisements promoting skin protection and influencing the attitude and practice of the population toward photoaging and photoprotection, but lack of professional and accurate information, or insufficient public attention to relevant knowledge.Moreover, some advertisements are too short to allow any knowledge transmission and only insist on a specific behavior.Another explanation might be that a lower level of knowledge led to a lower acknowledgment of the possible barriers to photoaging protection 32 .People with higher knowledge about a specific condition can be more fatalistic regarding that condition 33 .Still, that specific relationship will have to be investigated in more detail.
There are several limitations to this study.Although the researchers were spread across China, there may still be selection bias, and the need for cell phone use for online questionnaire respondents might exclude many older people.In addition, for questionnaire-type studies, there may be social desirability bias 34 in which although we designed incorrect question stems in the knowledge dimension, participants may show a learned characteristic by answering affirmatively to a question that is unclear in itself, thus making the knowledge score high.
In conclusion, this study suggest that the Chinese public's KAP toward photoaging needs to be improved, especially in terms of knowledge.A good attitude might lead to good practice.In the future, the Chinese population will be educated, and by promoting their good attitude, good practice will be obtained.

Study design and participants
This web-based cross-sectional study was conducted between January 2023 and March 2023.The participants were required to be ≥ 18 years of age, excluding questionnaires with incomplete responses.The study was approved by the ethics committee of the Southwest Hospital of Army Medical University approved this study (NO.KY2023010).Informed consent was obtained from all study participants.

Procedures
A self-administered questionnaire was designed for the study based on the WHO KAP development guideline 35 , Treatment of Photoaging 36 , and Skin cancer and photoprotection in people of color: A review and recommendations for physicians and the public 37 .This questionnaire contained four parts, including (1) participant demographic characteristics, including gender, age, residence type, education level, occupational type, household monthly per capita income, and marital status, (2) the knowledge dimension, which consisted of 12 questions about photoaging, with a score of 1 for correct answers and 0 for incorrect or unclear answers, ranging from 0 to 12, (3) the attitude dimension, which consisted of eight questions, all using a five-point Likert scale, ranging from "extremely positive" (5 points) to "extremely negative" (1 point), with a score of 8-40 points, and 4) the practice dimension, which consisted of 11 questions, also using a five-point Likert scale, ranging from "always" (5 points) to "never" (1 point), with a score of 11-55 points.Higher scores indicated more favorable KAP.A score greater than 75% was considered good, in the range of 60-75% was considered moderate, and less than 60% was considered poor.
After the questionnaire was designed and modified with reference to comments made by three experts (two dermatologists and one epidemiologist), a small pretest (134 copies) was conducted before the final questionnaire was formally released; the Cronbach's α was 0.913, and the KMO was 0.852, suggesting a high degree of consistency within the questionnaire.To ensure nationwide participation, we enlisted local volunteers from the seven sub-regions of China, namely Northeast, East, North, Central, South, Southwest, and Northwest.These volunteers were trained, briefed on the study's purpose and the necessary precautions, and deployed using the convenience sampling method for placement.The Questionnaire Star (Changsha Ranxing Information Technology Co., Ltd.) was used to construct the online questionnaire and generate a Quick Response (QR) code.The participants scanned the sent QR code through WeChat to log in and fill out the questionnaire.To ensure the quality and integrity of the questionnaire results, the participants had to authenticate when answering, each IP address could only be submitted once, all items were mandatory, and a verification code had to be entered manually when submitting.Members of the researchers' team checked all questionnaires for completeness, internal coherence, and reasonableness.

Figure 1 .
Figure 1.The distribution of the recruitment population in each region.*This map does not contain 1 foreign participant, accounting for 0.12%; the islands around China are not shown in this map.

Figure 2 .
Figure 2. The score distribution of the "attitude" dimension.*P refers to a positive formulation of the topic, N refers to a negative formulation of the topic, and what is shown in this figure is already the result adjusted for the assignment.

Figure 3 .
Figure 3.The score distribution of the "practice" dimension.*P refers to a positive formulation of the topic, N refers to a negative formulation of the topic, and what is shown in this figure is already the result adjusted for the assignment.

Table 1 .
Baseline characteristics and KAP scores.The P-values refer to the comparison of the values of the difference variables (e.g., male vs. female) for each KAP dimension.

Table 4 .
Multivariable linear regression analysis of the factors influencing practice.